London - They have been one of the retail sensations of the Christmas season.
Sales of eReaders, the handheld devices on to which electronic books can be downloaded, rocketed through December.
It is good news for makers such as Amazon, which produces the best- selling Kindle and collects 30 percent of the price of downloaded books.
But there are fears that their profits could be hit by a wave of pirate eBooks available to download for free.
Just as pirates and websites including Napster undermined the music industry by putting music on the web for free, so the same is now happening with eBooks.